Răspuns:
a)4/19×(1/3+1/4) = 4/19×7/12 = 1/19×7/3 = 7/57
c)(2/5×31/3-1)×14/5+1/10 = (2/5×10/3 - 1) × 9/5+1/10=(2×2/3 - 1)×9/5+1/10=(4/3 - 1) × 9/5 + 1/10 = 1/3 × 9/5 + 1/10 = 3/5 + 1/10 = 7/10
